Incomplete fixation of tissue can result in a number of artifacts in the histologic sections.
Manifestations of poor/incomplete fixation:
(1) cracking of tissue sections floating on the water bath
(2) smudgy or muddy nuclei
(3) poor maintenance of cellular morphology
Causes of poor fixation:
(1) insufficient time in fixation
(2) amount of fixative insufficient for the tissue
(3) depleted fixative
(4) large tissue block with insufficient fixative penetration
Steps to avoid artifacts:
(1) Use properly prepared fixative
(2) The ratio of fixative to tissue should be 15:1 or 20:1.
(3) Tissue blocks should be cut thin.
(4) The tissue should be in fixative as long as feasible (ideally > 30 hours; practically > 12 hours if possible).
